Limiting carbohydrates: an alternative to fasting

Intermittent fasting is a good strategy to adopt to lose weight, but also to improve various health parameters. However, it is not always easy to respect these constraints. For example, when following a 5:2 fast, you must severely restrict your calorie intake two days a week, which requires discipline and willpower.

This is why researchers are wondering whether other dietary modifications, less difficult to follow, would be as effective in improving metabolic health parameters. A solution seems to be emerging: reduce carbohydrates rather than calories. “My latest study shows that you don’t need to severely restrict calories to get the metabolic benefits of intermittent fasting, explains Adam Collins, associate professor of nutrition at the University of Surrey (1). Simply restricting the number of carbs you eat twice a week may be enough to improve your metabolic health. »

Read: Eating Fewer Carbs Leads to Burning More Calories

Metabolic improvement with or without fasting

In a previous study, Adam Collins’ team found that after a day of fasting the body burned fat better the next day (2). “Fasting allowed the body to switch from using carbohydrates to using fats. This effect was maintained during the fast and the following day. » But why does fasting or calorie restriction have this effect on fat utilization? Is it because of the reduction in carbohydrate intake? If so, this would mean that it is mainly the restriction of carbohydrates that is important, more than the reduction of calories.

To find out if it is caloric restriction or the reduction of carbohydrates which allows this metabolic effect on the use of fats, the researchers recruited 12 overweight or obese adults (3). Participants were put on a very low-carb diet for one day. Another day, they followed a calorie-restricted diet (about 75% fewer calories than they would normally eat). After each day, they ate a high-fat, high-sugar meal (similar to an English breakfast) to see if their bodies burned fat easily.

“We found that by simply limiting carbohydrates, without undergoing extreme caloric restriction, we can reap the metabolic effects associated with short-term fasting, explained Adam Collins (4). In other words, restricting carbohydrates may have the same favorable metabolic effects as fasting. »

These results will need to be confirmed on a larger sample of participants. “We are currently testing the feasibility of an intermittent carbohydrate restriction diet, or a 5:2 low-carb diet. So instead of restricting calories two days a week, you would restrict the number of carbs you eat twice a week. If this diet proves beneficial, it would provide the benefits of fasting without restricting calories on fasting days.”

To find out more: The Big Book of Metabolic Health

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